Snap-action contact blades have been used for many years in electrical switches to open or close electrical circuits by depressing a button or turning a knob or moving a lever or the like to apply an actuating force against the blade and that automatically returns the circuit to its original condition upon returning the button, knob, lever, or other means to its original position and thereby removing the force from the blade.
Such prior art type contact blades have characteristically featured a thin resilient plate having the electrical contact secured to one end and having an elongate opening having either one or two curved tongues extending thereinto that are adapted to engage some type of anchor on the switch which, in conjunction with means for securing the opposite end of the plate, provides a resilient cantilevered mounting for the plate.
Examples of plate-like contact blades having a singular tongue are respectively disclosed in U.S. Pat. Nos. 3,967,369 and 4,644,115, the disclosures of which are incorporated herein by reference.
Examples of plate-like contact blades having two opposed tongues are respectively disclosed in U.S. Pat. Nos. 3,532,840; 3,449,534; and 3,944,768, the disclosures of which are incorporated herein by reference.
An example of a plate-like contact blade having a central portion intermediate a pair of curved tongues is disclosed in U.S. Pat. No. 3,989,914, the disclosure of which is incorporated herein by reference and an example of a plate-like contact blade similar to the former but having two pairs of opposed tongues is disclosed in U.S. Pat. No. 4,499,346, the disclosure of which is incorporated herein by reference.
All of the above contact blades, however, require the primary plate member be secured to the switch in some manner either at or near the center or at or near the end opposite to that at which the electrical contact is located.
The contact blade of the present invention departs from the practice of utilizing a resilient plate with one or more curved tongues that must be secured to the switch either at or near the center or at or near the end opposite to that at which the electrical contact is mounted by providing a resilient curved tongue intermediate a pair of spaced-apart support legs that respectively extend from the same side of the contact blade to greatly enhance compactness and which cooperate with each other to resiliently support the blade on the switch frame and are respectively anchored thereto in a manner providing a broad distance along specified surfaces on the opposite side of the plate upon which the activating force may be applied for activating the switch.
The contact blade of the present invention is not the first to have support legs extending from the main body of the blade, however, for such are utilized in a contact blade manufactured and sold as a "Series 770" switch by the assignee of this invention but which differs substantially from the contact blade of the present invention by having the support legs on the opposite side of the blade from which the tongue extends which substantially lessens its compactness.